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package unc.pds.servlets;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.jms.Session;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 *
 * @author Михаил
 */
public class CaptchaServlet extends HttpServlet {
   
    /** 
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("image/png");
        request.setCharacterEncoding("UTF-8");
        OutputStream out = response.getOutputStream();
        try {
            int width = 140;
            int height = 50;
            int cNum = 4;
            BufferedImage captcha = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics captchaGraphics = captcha.getGraphics();
            Random r = new Random();
            captchaGraphics.setColor(Color.white);
            captchaGraphics.fillRect(0, 0, width, height);
            int charWidth = width/cNum;
            String str = "";
            String elegibleChars = "ABCDEFGHJKLMPQRSTUVWXYabcdefhjkmnpqrstuvwxy23456789";
            char[] chars = elegibleChars.toCharArray();
            int x = 0;
            for (int i = 0; i < cNum; i++) {
                char nextChar = chars[r.nextInt(chars.length)];
                str += nextChar;
            }
            Font captchaFont = new Font("Arial",Font.BOLD,36);
            captchaGraphics.setFont(captchaFont);
            captchaGraphics.setColor(Color.BLACK);
            captchaGraphics.drawString(str, 10, 40);
            ImageIO.write(captcha, "PNG", out);
            HttpSession session = request.getSession();
            session.setAttribute("captcha", str);
        } finally {
            out.close();
        }
    } 

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    } 

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** 
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}
